Phlebotomy, or bloodletting, is the longest-running tradition in medicine. It originated in
the ancient civilizations of Egypt and Greece, persisted through the Medieval,
Renaissance, and Enlightenment periods, flourished in Arabic and Indian medicine, and
lasted through the second Industrial Revolution. The practice continued for 2,500 years
until it was replaced by the techniques of modern medicine.

Doctors bled patients for every ailment imaginable. They bled for pneumonia and
fevers, back pain and rheumatism, headaches and melancholia; even to treat bone
fractures and other wounds. Yet there never was any evidence that phlebotomy did any
good.

Bloodletting was based on an ancient system of medicine
in which blood and other bodily fluid were considered to
be "humors" whose proper balance maintained health.
Sick patients were thought to have an imbalance of their
humors, which bloodletting was thought to restore.

Most bloodletters would open a vein in the arm, leg or
neck with small, fine knife called a lancet. They would tie
off the area with a tourniquet and, holding the lancet
delicately between thumb and forefinger, strike diagonally
or lengthwise into the vein. (A perpendicular cut might
sever the blood vessel.) They would collect the blood in measuring bowls, exquisitely
wrought of fine Venetian glass.

Bleeding was as trusted and popular in ancient days as aspirin is today. The Talmudic
authors laid out complex laws for bloodletting. Medieval monks bled each other several
times a year for general maintenance of health. Doctors devised elaborate charts
indicating the most favorable astrological conditions for bleeding.

It wasn't until well into the 19th century that people began to question the value of
bloodletting. Scientists such as Louis Pasteur, Joseph Lister, and Robert Koch showed
that germs, not humors, were responsible for disease. Furthermore, medical
statisticians tracking case histories began to collect evidence that bloodletting was not
effective. Eventually the practice died, although it continued in some parts of rural
America into the 1920s.

Phlebotomy is almost never used anymore, except for certain rare conditions. One is
hemachromatosis, a genetic condition affecting 600,000 to 1,000,000 Americans in
which the body stores too much iron. One way to treat this is to periodically drain some
of their iron-rich blood, which restores the mineral's proper balance.